With the rapid development of the technology, the light-emitting diode (LED) is widely applied to display device, traffic signals, lighting, medical devices and various electronic products.
There are several ways using LEDs to produce white light: (1) mixing blue light, red light, and green light which are respectively generated from blue, red, and green LED(s) to produce the white light; (2) using ultraviolet light-emitting diode(s) exciting phosphor to produce the white light; and (3) using blue LED(s) exciting yellow phosphor to produce the white light by the complementary colors.
Some issues still remain in the aforementioned ways; therefore, the market is looking forward to the technology innovations.